Recently, as various types of surface-treatment agents for use in cosmetics, methylhydrogenpolysiloxanes have been widely used. Powders treated with methylhydrogenpolysiloxanes exhibit increased water repellency, and for this reason, characteristics of improving make-up durability are exhibited. However, since the methylhydrogenpolysiloxanes induce not only a reaction with the surface of powder, but also an intermolecularly-cross linking reaction during surface-treating, the rate of reaction is reduced. As a result, unreacted Si—H bonds remain on the surface-treated powders. Therefore, hydrogen may generate as a gas depending on the conditions, and this is dangerous in the presence of fire or the like. In addition, there are various problems of causing expansion of a cosmetic container, fogging of compact mirror and the like.
In order to solve the aforementioned problems, Japanese Unexamined Patent Application, First Publication No. H05-237360 proposes a method in which surface-treated powders are treated at high temperature so that Si—H bonds do not remain as much as possible. However, the aforementioned method cannot be applied to heat-sensitive powders such as yellow iron oxide, Red No. 202 and the like, and further improvements are needed.
Under the circumstances described above, as a method in which residual Si—H bonds are not produced, Japanese Unexamined Patent Application, First Publication No. H07-196946 proposes a surface-treatment method using a one-terminal alkoxy-modified silicone, and WO 2002/100356 proposes a surface-treatment method using an acryl-modified silicone having an alkoxysilyl group. However, in the case of using the one-terminal alkoxy-modified silicone, the amount of the alkoxy group is reduced, and for this reason, there is a problem in that low reactivity with the powders is exhibited. On the other hand, in the surface-treatment method using an acryl-modified silicone having an alkoxysilyl group, the acryl-modified silicone having a linear silicone is grafted on an acryl main chain, and for this reason, there is a problem in that sebum resistance and the like are not sufficient. In addition, powders surface-treated with the acryl-modified silicone having an alkoxysilyl group exhibit low compatibility with other raw materials for cosmetics, and there is a problem in view of stability in blending in cosmetics.
On the other hand, in order to ameliorate the problems caused by the linear silicones, a cosmetic raw material comprising a vinyl-based polymer having a carbosiloxane dendrimer structure at the side chain or a vinyl-based polymer having both a carbosiloxane dendrimer structure and a fluorinated organic group, as a main agent is proposed (see Japanese Unexamined Patent Application, First Publication No. 2000-63225; and Japanese Unexamined Patent Application, First Publication No. 2003-226611). However, Japanese Unexamined Patent Application, First Publication No. 2000-63225 and Japanese Unexamined Patent Application, First Publication No. 2003-226611 fail to describe application of various types of powders to surface treatments.